Make Phalcon\Mvc\Model\Validator::getOption/getOptions/isSetOption public

Fix #1904
Updated CHANGELOG
Problem with performance and getRouteByName
Changed variable name from camel case to underscores
Corrected returned value
Corrected NullLogger definition
Added checks if name is really a string

If there something else than a string was provided, then router was
segfauliting. Now there's a check and other names than strings won't be
taken into consideration at all.

Corrected names of variables from camelCase to understores.
Optimizations
Optimize Phalcon\Mvc\Model\Validator::appendMessage()
Added Session\Bag unit test and specific test for #1895
Fix #1905
Phalcon\Mvc\Model\Query optimizations
Optimize Phalcon\Mvc\Model::refresh()
Get rid of hardcoded constants
Updated arrays to use traditional syntax for 5.3 compatibility
Convert names to strings for comparison
Merge pull request #1900 from piteer1/1.3.0

Problem with performance and getRouteByName
Merge pull request #1927 from sjinks/issue-1904

Make Phalcon\Mvc\Model\Validator::getOption/getOptions/isSetOption public
Merge pull request #1928 from ianbytchek/1.3.0

Added Session\Bag unit test
Merge pull request #1929 from sjinks/issue-1905

Fix #1905